Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

984
FXUS63 KLOT 032116
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
316 PM CST Tue Feb 3 2026

.KEY MESSAGES...

- Lake effect snow showers will meander across the northeastern
  Illinois and northwestern Indiana shores of Lake Michgian late
  this evening into early Wednesday AM, though accumulations
  should stay below an inch.

- Forecast high temperatures are above the freezing mark
  areawide by Friday, marking the end of a prolonged stretch of
  daily highs below 32 degrees.

- Periodic (mainly light) snow chances exist through the end of
  the week, with the highest chances (30-40%) Thursday night,
  potentially falling as a wintry mix.

- A pattern change toward warmer temperatures (highs and lows
  both above freezing) may materialize by the middle of next
  week.

&&

.DISCUSSION...
Issued at 316 PM CST Tue Feb 3 2026

Through Wednesday night:

After having cleared out earlier in the day, low stratus has
begun marching inland across the Chicago metro and into
northwest Indiana this afternoon. Expect this to continue
expanding southward through the rest of the evening. Can`t rule
out occasional flurries beneath this cloud layer as well.
Heading into the late evening and overnight period, weak
convergence over the lake paired with saturation touching the
DGZ may allow for a band of lake effect snow to develop and
meander along the southern Lake Michigan shore through the night.
Confidence in how far inland this reaches is on the lower side
but can`t rule out a localized dusting of snow (0.1 to locally
0.5") over parts of Cook, Lake (IN) and Porter Counties, highest
near the lakeshore. Any lingering lake effect snow showers
likely shift back out over the lake Wednesday morning. The rest
of the day on Wednesday looks dry areawide with high
temperatures still cool, in the 20s.

Thursday:

The northwest upper level flow pattern will remain favorable
for multiple waves to dive across the region bringing periodic
chances for (mainly light) wintry precipitation through the end
of the week. This first of which arrives Thursday morning.
While this feature appears rather moisture starved, given modest
warm advection ahead of this feature still suspect that we may
get a quick hit of snow showers/flurries as the wave moves
overhead, potentially enhanced locally by seeder-feeder
processes depending on coverage of the low-level stratus. While
flurries appears to be the most likely outcome, localized
dustings of snow can`t be ruled out. Once the snow/flurries end,
southerly winds will help advect warmer air into the area
through the day on Thursday, with forecast high temperatures in
the low to mid 30s north of I-57, with upper 20s south.

Thursday night - Friday morning:

A more focused mid-level shortwave dives across the area late
Thursday night into Friday morning and is expected to bring a
period of wintry precipitation to the area. Models are coming
into a bit better agreement in the local area seeing at least
some precipitation with this and have accordingly boosted
precipitation chances into the 30-40% range (and will likely
need to be increased further with later updates). However,
there remain questions regarding the dominant precipitation type
with this feature. A sampling of forecast vertical temperature
profiles suggests there could be a period of snow, sleet, and/or
freezing rain over parts of the area. Steepening mid-level
lapse rates situated within the DGZ will be supportive of
efficient snow production which could help cool the column even
amidst modest warm advection, leading to snow being the
dominant precipitation type. However, in the event of less
efficient wet-bulb cooling and/or stronger warm advection, we
could end up with a wintry mix of snow, sleet and/or freezing
rain. Have introduced a slight chance (20%) for sleet with this
update but have held off on including freezing rain for now
given the lower confidence in what would be potentially more
impactful, even with very light precipitation amounts (under
0.05"). This will be a period to monitor over the next couple
of days as confidence in the details increases. Any remaining
snow/precipitation will gradually shift southeast of the area
through mid morning Friday.

Friday afternoon:

In the wake of the early morning wintry precip, winds will turn
northwesterly during the day on Friday. While northwest winds
are typically associated with cold air advection here locally,
upstream temperatures will actually be warmer than what we will
have been experiencing previously. This should allow
temperatures to warm well into the mid-upper 30s, and
potentially lower 40s in some spots bringing an end to the long
stretch of sub-freezing temperatures for much of the area. This
"warmth" will be fairly short-lived, however, with temperatures
quickly falling late afternoon/early evening behind a cold
front, also potentially paired with a period of gusty snow
showers (20% chance) as low-level lapse rates steepen in the
wake of the front. Overnight lows are then forecast to drop
back into the low to mid teens.

This weekend through early next week:

The weekend will start off cooler, with highs in the mid 20s to
lower 30s with another weak wave potentially diving through the
region Saturday night which may result in a few snow showers (15%
chance), though there remain a fair amount of variability in
guidance this far out. Temperatures are then expected to
gradually warm each day through much of the upcoming week as we
undergo a pattern shift with upper level ridging building back
toward the region. In fact, many areas could see temperatures
well into the 40s by Tuesday. With extensive ice cover on area
rivers this will be a period to monitor for any potential ice
jam flooding developing as we head into an extended stretch of
above freezing temperatures.

Petr

&&

.AVIATION /18Z TAFS THROUGH 00Z THURSDAY/...
Issued at 1155 AM CST Tue Feb 3 2026

Aviation forecast concerns for 18Z TAFs:

- MVFR lake-induced stratocu for ORD/MDW/GYY develops this
  afternoon and persists into Wednesday.

- Period of lake-effect snow showers mainly for MDW/GYY tonight
  into Wednesday morning. IFR vis possible at times along with
  some minor accums.

A subtle trough pushing south across Lake Michigan at midday
will shift winds at ORD/MDW/GYY to NNE/NE shortly. This will
also spread lake-induced MVFR stratocu into these terminals
early this afternoon. Forecast soundings indicate this stratocu
layer is fairly shallow, and warmer than more favorable snow
crystal generation temps. Thus while can`t completely rule out a
few non-impactful flurries, do not think they`ll be significant
enough for TAF inclusion this afternoon except perhaps at GYY.

High-res models continue to indicate deepening cloud depth and
colder temps aloft and a more substantial snow shower potential
later this evening into early Wednesday morning, with guidance
primarily highlighting the MDW-GYY terminals. Periods of IFR
vis and some light accums (1" or less) are possible for these
locations. At this time, ORD looks to be just northwest of the
better snow shower coverage, though current probabilities (20%)
are below mentionable TAF criteria. Will have to monitor
position of the band later tonight in case this needs to be
included for ORD, which would likely be in the 07Z-13Z time
range if it occurred.

Otherwise, winds are expected to turn back to NNW later this
evening into Wednesday. Farther away from the lake, VFR
conditions are expected to prevail at DPA and RFD.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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